Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy.
PLoS One. 2012;7(2):e31770. doi: 10.1371/journal.pone.0031770. Epub 2012 Feb 22.
Intercepting a moving object requires accurate spatio-temporal control. Several studies have investigated how the CNS copes with such a challenging task, focusing on the nature of the information used to extract target motion parameters and on the identification of general control strategies. In the present study we provide evidence that the right time and place of the collision is not univocally specified by the CNS for a given target motion; instead, different but equally successful solutions can be adopted by different subjects when task constraints are loose. We characterized arm kinematics of fourteen subjects and performed a detailed analysis on a subset of six subjects who showed comparable success rates when asked to catch a flying ball in three dimensional space. Balls were projected by an actuated launching apparatus in order to obtain different arrival flight time and height conditions. Inter-individual variability was observed in several kinematic parameters, such as wrist trajectory, wrist velocity profile, timing and spatial distribution of the impact point, upper limb posture, trunk motion, and submovement decomposition. Individual idiosyncratic behaviors were consistent across different ball flight time conditions and across two experimental sessions carried out at one year distance. These results highlight the importance of a systematic characterization of individual factors in the study of interceptive tasks.
拦截移动物体需要精确的时空控制。已有多项研究探讨了中枢神经系统如何应对这一具有挑战性的任务，重点关注用于提取目标运动参数的信息的性质，以及确定通用控制策略。在本研究中，我们提供了证据表明，对于给定的目标运动，中枢神经系统并非唯一指定碰撞的时间和地点；相反，当任务约束较宽松时，不同的但同样成功的解决方案可以被不同的受试者采用。我们描述了十四个受试者的手臂运动学，并对六个受试者进行了详细分析，这些受试者在被要求在三维空间中接住一个飞行球时表现出相似的成功率。球被一个驱动的发射装置发射，以获得不同的到达飞行时间和高度条件。在几个运动学参数中观察到个体间的可变性，例如手腕轨迹、手腕速度曲线、撞击点的时间和空间分布、上肢姿势、躯干运动和亚运动分解。个体特有的行为在不同的球飞行时间条件和相隔一年进行的两次实验中是一致的。这些结果强调了在拦截任务研究中对个体因素进行系统特征描述的重要性。
